Vertical Shafts & Horizontal Drifts
CSS Vertical Shafts & Horizontal Drifts
A vertical shaft is a structure used for ventilation, emergency access, and construction operations during the construction of long tunnels. The conventional cast-in-place reinforced concrete method involves reinforcing bar assembly, formwork installation, and concrete pouring. However, this method generates numerous construction joints, which can negatively affect structural quality.
In addition, there is a high risk of safety accidents due to reinforcing bar assembly and formwork installation and dismantling at elevated locations. For example, during the construction of the SRT vertical shafts in 2016, five safety accidents occurred, resulting in five fatalities. Another major drawback of this method is the excessive construction period.
A horizontal adit connects the vertical shaft to the main tunnel. Typically, these structures are less than 50 meters in length. Longer sections generally require separate tunnel formwork systems, while shorter sections commonly use the cast-in-place construction method. However, the vertical shaft construction process cannot be carried out simultaneously with tunnel formwork or cast-in-place works, creating scheduling constraints. As a result, despite the relatively small scale of the structure, the overall construction period becomes significantly extended and project costs increase.
Solution.1
The corrugated steel plate vertical shaft is a new construction technology (No. 804 “Construction technology for vertical shafts assembled modularly on the ground using flanged corrugated steel plates”) that ① installs and assembles modular corrugated steel plates on the ground, ② installs and assembles stairwells, air conditioning rooms, and other necessary installations on a single modular corrugated steel plate, ③ uses a crane to connect them to the modular corrugated steel plates below, and ④ assembles them using a flange method.
This is a construction method that not only improves the compressive strength, flexural strength, and waterproof performance of the joints between modules, but also improves safety by eliminating air shortening and high-altitude work.
Transverse shaft (inner side) install
external assembly
DAEDOTech Co., Ltd @Copyright
DAEDOTech Co., Ltd @Copyright
Stairs, elevator room
Air conditioning room ground assembly
Solution.2
The method of applying a horizontal shaft connecting the main line and the vertical shaft is a new construction technology (No. 804) method that involves ① assembling corrugated steel plates inside an excavated tunnel ➞ ② pouring concrete onto the back surface through grouting holes previously made on the top and side of the corrugated steel plates ➞ ③ pouring concrete onto the back surface.
This is a construction method that finishes the construction from the inside, and since the corrugated steel plate itself has the rigidity and plays the role of a formwork, the construction period is shortened compared to a multi-stage process (reinforcement, formwork, shoring, curing) such as concrete. In addition, for accurate construction quality, ① excavation (check for over-excavation and under-excavation) and installed temporary facilities before design ➞ ② based on 3D measurement (Leica P30®, Cyclone®, ±3mm) ➞ ③ after creating a manufacturing drawing, it is manufactured precisely in the factory, and construction is done on site with only bolt assembly.
In Korea, our method has been used in 14 locations, including the SRT and Gimpo Urban Railway, since 2015. Furthermore, unlike concrete methods, our method allows for passage of the horizontal shaft during construction, ensuring greater convenience during construction.
Patents Registered: 10-1628223, 10-161172, 10-1621456, 10-1801054, 10-1629286, 10-1638478
Open Caisson (Breakwater Shore)
Structures that must be installed down to hard ground layers often use wells (open caissons) as foundation systems. Traditionally, these wells have been constructed on site in circular form using either reinforced concrete or thick steel plates. However, with the increased structural stiffness of the deep corrugation corrugated steel structure EXSCor® (utilizing 10 mm thick steel plates and a double-shell structure), it has become possible to apply this system to bridge caisson foundations, port breakwater shores, and thermal power plants that extensively use seawater, providing both economic advantages and rapid construction.
For improved corrosion resistance, high-strength seawater-resistant steel for port and marine structures, POSCO Poseidon500, can be applied. In addition, 3D FEA analysis enables comprehensive evaluation under a wide range of environmental conditions.
